Please help me with this math problem

(z-9)(z+2)

Step-by-step explanation:

U have to find numbers which when u multiply u get -18 and subtract u get -7

-18= -9×+2,2-9=-7

Z²+2z-9z-18

Z(z+2)-9(z+2)

(Z-9)(z+2)

(z+2)(z-9)

Step-by-step explanation:

 to solve for this you need to find two numbers that if multiplied together they give you negative 18 and at the same time adds up to -7.

Those two numbers could be  -9 and 2 .

now rewrite the expression like this.

  Group them  

(    Factor it out z in the first grouping

z(z +2)  -9(z + 2)          factor out  x+2

(z +2 ) (z-9)

x + 107

step-by-step explanation:

let's say that the number he had before the mistake was x. then, he will have 107 dollars more than this, so the answer is x + 107.